Printing telegraph system



0a. 6,1942. c. J. FITCH 2,297,758

vPRINTING TELEGRAPH SYSTEM Filed May 8, 1941 A TTORNE Y Patented Oct. 6, 1942 UNITED STATES PATENT OFFICE PRINTING TELEGRAPH SYSTEM Application May 8, 1941, Serial No. 392,407

5 Claims.

This invention relates to a printing telegraph system, and more particularly to such systems, utilizing start-stop impulse distributing means.

The present invention constitutes a modification of the system described in the copending ap plication SerialNo. 370,675 filed December 18, 1940.

In the said copending application, provision is made for controlling the operation of the impulse generating and distributing means by means of a start-stop electronic oscillation generator; whereas, in the present application, a pair of contacts are provided, which are opened and closed alternately under control of the stepping magnets of the distributing means, for controlling alternately the effects of resistor-capacitor networks. The said networks are arranged to control the alternate energizations of the impulse distributing means, control magnets and the impulse generating means.

Accordingly, an object of the present invention resides in the provision of alternately operated control means, such as contacts arranged to be opened and closed, alternately, under control of the impulse distributing means, for controlling the successive operations of the impulse generating and distributing means.

Another object of the invention resides in the provision of means in the impulse distributing means for controlling the latter and the associated control means in a start-stop manner.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawing, which discloses, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawing:

Fig. l is a wiring diagram showing the circuit connections of the control elements of a preferred type of signaling system.

Fig. 2 shows the wave forms of the variably timed signals generated by the system.

Referring now to the circuit diagram, the system to be described is of the start-stop type, wherein a continuous signal or current condition is impressed upon the associated transmission medium at the times character signals are not impressed thereupon.

The present description will be limited to F means for initiating and transmitting the permutation signals, which incorporate the step by step impulse distributing means and the associated start-stop control means. Suitable means for receiving the signals and recording the charn n f acters in accordance with the received signals are well known to those skilled in the art.

The impulse distributing means, generally indicated by the reference character D, comprises two stationary conducting ring assemblies including the rotatable contacts 9 and I0, respectively, which are adapted to engage and connect progressively the individual conducting segments H to the related common conducting segment l2. The said contacts are rotated by a shaft indicated by the reference character [3, having a ratchet I4 affixed thereto. The said contacts 9 and I0, shaft l3, and ratchet M are advanced step by step by the spring urged pawls l5 pivotally supported by the individual pivoted armature arms [6 of the control magnets MI and M2. Each step the contacts are advanced a distance equal to half the length of the longer conducting segments H, such as segments P, and l-6. The lengths of the remaining segments H such as O and S are half that of the previously mentioned segments. The segments and contacts are so arranged that, when one of the contacts 9 transfers, for example, from segments I to 3, or 3 to 5, one of the contacts I0 sweeps across the central portions of the 2 or 4 segments, respectively, and when one of the contacts [0 transfers, for example, from segments 2 to 4, or 4 to 6, one of the contacts 9 sweeps across the central portions of the 3 or 5 segments, respectively.

A pair of control contacts MCI and M02 are provided, and suitably disposed with respect to the armature arms I6, so that upon energization of the magnets Ml or M2, the contacts MCI or MCZ, respectively, are closed by the related armature arms, as shown in the figure.

The said contacts MCI and MC2 are connected to the individual resistor-capacitor networks R,l---Cl, and RZ-CZ, respectively, which networks in turn are connected to grids 22, 23, and grids 20, 2|, respectively, of the electron discharge devices TI and T2, which are of the double triode type.

The anode elements 24 and 25 of device Tl are connected to one of the terminals of the magnets MI and M2, the other terminals of which are connected to the positive terminal 28 of the power supply. The anode elements 26 and 21 of device T2 are connected to the individual common conducting segments l2 of the impulse distributing means. The cathode elements 3| and 32 of the said devices are connected to the negative terminal 29 of the said power supply. A suitable biasing potential supply 33 is provided to impress, by means of the variable resistors 34 zero biasing potential.

and 35, negative biasing potentials on grids 22, 2| and 22, 23, respectively, with respect to the related cathodes 3| and 32. Normally, the said biasing potentials are efiective to render the related triode sections of devices Ti and T2 nonconductive.

It will be understood as the description progresses, that the resistor-capacitor networks R|C| and R2C2 are effective under certain conditions to alter the biasing potentials impressed upon grids 23, 2|, 22, and 23, alternately so as to render the related triode sections conductive accordingly. In this manner,.it will be seen, that magnets Mi and M2 are energized alternately to advance step by step the contacts 9 and i0, thereby making'the individual control circuits, associated with the distributor D, available successively. The triode sections of device T2, when rendered conductive alternately, control the conductivity of the control circuits or channels made available during the operation of the distributor. The timed interval during which the distributor is operated will be referred to as a signaling cycle.

The control circuits 33, or signaling channels,

are connected to the individual conducting segments Ii, namely, |--6, and the normally open contacts TCi-TCt, respectively. The said contacts TC|-TC3 represent diagrammatically the well known control contacts which are operated permutatively to control the initiation of the character signals, by suitable means, such as the transmitting teleprinter devices shown in U. S. Patents Nos. 1,214,515 and 2,161,564. Upon operation of any one contact or any combination of contacts of the group TC|TC3, the normally closed contacts TC are opened. The latter are connected by conductor 37 to the O conducting segment of the distributor. The contacts are also connected by a common conductor 38 to the P segment of the distributor and the cathode circuit of electron discharge device T3, which is of the double triode type, and the elements of which are connected as a well known type of oscillator. The output circuit of the device T3 includes the primary winding of transformer 39, the secondary winding of which can be connected to any suitable transmission medium.

Now, so long as the contacts TCi-TC| remain in the normal positions shown, a circuit can be traced from the positive terminal 23 of the power supply, to conductor ii], the center tap connection of the primary winding of transformer 39, anode and cathode elements of device T3, conductor 3S, normally closed contacts TC, conductor 31, the O conducting segment, contacts H), the S conducting segment, conductor 4|, resistors 42 and 3t, battery 33, and conductor 43 to the negative terminal 29 of the said power supply.

The current flow in this circuit is of relatively low value, however, the voltage drop across resistor 34 is eiTective to neutralize the negative biasing potentials impressed by battery 33 upon grids 2|] and 2| of devices TI and T2, respectively, thereby placing the said grids at substantially Under the described conditions, the triode sections of devices Ti and T2 controlled by grids 2E! and 2| are rendered conductive.

Another circuit can be traced from the positive terminal 28 of the power supply to conductor ii], center tap connection of the primary winding of transformer 39, anode and cathode elements of device T3, conductor 38, the P seg- 'ment H of the uppermost conducting ring, contacts 9, the related common conducting segment I 2, conductor 34, anode 26, and cathode 32 of device T2, conductor 43 to terminal 29 of the said power supply, thereby permitting the device T3 to oscillate and impress the continuous signal upon the secondary winding of transformer 39 and associated transmission network. This continuous signal condition is indicated by the character A in Fig. 2.

Still another circuit can be traced from the positive terminal 23 to resistor 35, magnet Ml,

anode 2 5 and cathode 3| of device TI, to concontacts MCi in a closed position.

With the contacts MCI closed, a relatively high positive potential from terminal 28 of the power supply cannot be impressed upon grids 22 and 23 of devices Ti and T2, respectively. However, upon operation of any one of the contacts TC|- TC3, or any combination thereof, contacts TC are opened, thereb removing the positive potential from the said grids 2E] and 2|. The normal negative biasing potentials'impressed upon these grids, namely, 20 and 2| are eiiective now to render the controlled triode sections of devices Ti and T2 non-conductive. Thus, magnet MI is -deenergized and device T3 is rendered non-conductive. In the type of system referred to, the cessation of the continuous signal condition is termed the start signal and is indicated by the character B in Fig. 2.

Upon deenergization of magnet Ml, the associated armature I6 is released, and the contacts MCi are opened to impress a relatively high positive potential from terminal 28 of the power supply upon grids 22 and 23 of devices Ti and T2, respectively, through the resistor RI and condenser Ci. This positive potential overcomes the biasing effect of the battery 33, and thus renders the triode sections of devices T| and T2 controlled by grids 22 and 23 conductive. Consequently, the magnet M2 is energized by means of the circuit completed from terminal 28 to magnet M2, anode 25 and cathode 3i of device TI, and conductor 43 to terminal 29. Upon energization of magnet M2, the contacts MC2 are closed to connect the lowermost terminal of resistor R2 to conductor 43 to effect discharging of the condenser C2 through resistor 33, which renders the grids 20 and 2| more negative with respect to the cathode potential. Grids 22 and 23 remain positive until condenser CE is fully charged through resistor .Ri, whereupon grids 22 and '23 become negative again to effect deenergization of magnet M2, and in turn open contacts MCZ. This alternate control ofgrids 23, 2| and 22, 23, and energization and deenergization of magnets MI and M2 continues until the positive potential mentioned hereinabove-isimpressed upon conductor il and resistor 412.

Thus, it is seen, that a vibratory conditionis set up to influence devices T! and T2, and the stepping magnets MI and M2 of the distributor D, the period of vibration depending-uponthe 'C and R values of the RI Cl and R2, C2 networks. This vibratory condition continues until the contacts 9 and ID are returned to the normal condition shown in Fig. 1, when it is assumed the contacts T are closed, to complete the described circuit from the positive terminal 28 of the power supply to conductor M and resistor 42 to impress a steady positive potential upon grids 20 and 2 I, thereby restoring the normal non-vibratory conditions described hereinabove. During the said vibratory period, or signaling cycle, the contacts 9 and ID are advanced eight steps before returned to the normal home position.

In order to describe briefly how the various signaling channels or circuits are energized or rendered conductive as they are made available, assume that when the said contacts TC are opened that contacts TCI, TC4, and T are closed. Now, during the first step, the start signal (see B in Fig. 2) is initiated as described. During the second step, the triode section controlled by grid 2| is conductive, and since contacts TCI are closed, a circuit can betraced as follows: from terminal 28 to conductor 4!), device T3, conductor 38, contacts TCI, the l segment II of distributor D, contacts 9, common segment l2, conductor 44, anode 26 and cathode 32 of device T2, conductor 43 to terminal 29, thus rendering device T3 conductive to generate the first character signal of the combination as indicated at C in Fig. 2. During the said second step, contacts I0 engage the 2 segment, but no circuit can be completed therethrough since contacts TC2 are open; and assuming for the moment that the latter are closed, no circuit could be established at this time, due to the fact that the triode section controlled by grid 23 is non-conductive.

During the third and fourth steps, no signals are generated as indicated at D and E in Fig. 2. During the fifth step, the device T3 is rendered conductive since contacts TC4 are closed and the triode section controlled by grid 23 is conductive at this time to generate the second signal of the combination as indicated at F in Fig. 2. During the sixth step .the third signal indicated at G in Fig. 2 is generated, since contacts TC5 are closed and the triode section of device T2 controlled by grid 2| is conductive at this time. During the seventh step, the device T3 is nonconductive, and during the eighth step, the said device T3 is rendered conductive continuously to generate the continuous signal indicated A in Fig. 2.

It is remembered that this condition is established by the closed contacts TC and the circuits established through the P segment and the O and S segments. The vibratory conditions described are interrupted by these circuits, and are resumed only upon the opening of the said TC contacts to prevent the impression of the steady positive potential upon grids and 2| of devices TI and T2, respectively. From this detailed description, it is evident how various other signal combinations can be initiated under control of the contacts TC l-TCB, and the described impulse generating and distributing means.

While there has been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as in dicated by the scope of the following claims:

What is claimed is:

1. A system of the character described having impulse distributing means and actuating means therefor, the latter including a pair of electromagnets, control means including electron discharge paths, one for each electromagnet, for effecting the energization of said electromagnets, a plurality of resistor-capacitor networks, one for each discharge path, each network arranged to control the conductivity of the related discharge path, and a pair of contact means, one for each network, operated alternately and directly by the said electromagnets for rendering the networks efiective to cause the related discharge paths to become conductive, thereby effecting alternately the energization of said electromagnets.

2. A system of the character described having impulse distributing means and actuating means therefor, the latter including a pair of electromagnets, control means including a pair of electron discharge paths for effecting the energization of said electromagnets in an alternate manner, a plurality of resistor-capacitor networks, one for each discharge path, for controlling the conductivity of .the electron discharge paths, and means controlled alternately and directly by the said electromagnets for rendering the said networks efiective to cause the related discharge paths to become conductive.

3. A system of the character described having impulse distributing means and actuating means therefor, the latter including a pair of electromagnets, control means for eifecting the energization of said electromagnets alternately, and means controlled alternately and directly by said electromagnets including means for rendering the said control means effective to energize at alternate intervals the said electromagnets.

4. The invention set forth in claim 3 wherein the said controlled means also includes a pair of electrical contact means which are operated alternately and directly by the said electromagnets.

5. The invention set forth in claim 3 wherein the said control means includes a pair of electron discharge paths for effecting the energization of said electromagnets alternately.

CLYDE J. FITCH. 

